+ Site Statistics
+ Search Articles
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on Google+Follow on Google+
Follow on LinkedInFollow on LinkedIn

+ Translate

Regulation of gonadotropin receptors on cultured porcine Leydig and Sertoli cells: effect of potassium depletion

Endocrinology 118(6): 2254-2261
Regulation of gonadotropin receptors on cultured porcine Leydig and Sertoli cells: effect of potassium depletion
We have examined the role of the NaK-ATPase pump activity on the ligand-induced down-regulation of gonadotropin receptors in cultured porcine Leydig and Sertoli cells. In both cells, inhibition of the NaK pump by ouabain produced a depletion of intracellular K+ levels (ID50, 10(-7) M) after a lag period of about 8 h. In the absence of ligand, the number of FSH receptors in ouabain-treated Sertoli cells was unaffected or slightly reduced, whereas a 2-fold increase in the number of human CG (hCG)/LH receptors with small changes in the binding affinity was observed in Leydig cells treated by ouabain. The effect of ouabain was dose dependent. Differences were also observed in the down-regulation process of gonadotropin receptors in ouabain-treated cells. The hCG-induced receptor loss in Leydig cells was completely reversed by ouabain whereas the drug had no effect on ligand-induced loss of FSH receptors in Sertoli cells. Similar results were observed when the cells were incubated in K+-free medium. Kinetics studies with labeled hCG have shown that ouabain treatment slows down significantly the rate of [125I]iodo-hCG internalization (t 1/2, 18 h; control cells, t 1/2, 6 h), but had no effect on the degradation of internalized hormone. The internalization of receptor-bound [125I]iodo-hCG was also reduced when Leydig cells were incubated in K+-free medium, but was restored when this medium was supplemented with rubidium. The influence of the NaK pump on the receptor regulation of a ligand common to both types of cells, such as epidermal growth factor, was studied under the same experimental conditions. Neither ouabain nor K+-free medium were able to prevent the epidermal growth factor-induced reduction of receptor levels in Leydig and Sertoli cells. Thus, it appears that modulation of ligand-induced receptor loss by depletion of cellular K+ levels is not dependent on the cell type, but on the ligand-receptor complex. The data also show a striking difference in the dynamics of gonadotropin-receptor interaction of two structurally related hormones.

Accession: 006288239

PMID: 2422017

DOI: 10.1210/endo-118-6-2254

Related references

Regulation of gonadotropin receptors and steroidogenesis in cultured porcine Leydig cells. Endocrinology 110(3): 933-940, 1982

Regulation of gonadotropin receptors, gonadotropin responsiveness, and cell multiplication by somatomedin-C and insulin in cultured pig Leydig cells. Journal of Cellular Physiology 129(2): 257-263, 1986

Expression and regulation of transforming growth factor-beta 1 messenger ribonucleic acid and protein in cultured porcine Leydig and Sertoli cells. Endocrinology 134(5): 2079-2087, 1994

Regulation of gonadotropin receptors and steroidogenesis in cultured procine Leydig cells. Endocrinology 110(3): 933-940, 1982

Gonadotropin-induced changes in the luteinizing hormone receptors of cultured Leydig cells. Evidence of up-regulation in vitro. Journal of Biological Chemistry 258(12): 7322-7330, 1983

Primary cultures of Leydig cells from rat, mouse and pig: advantages of porcine cells for the study of gonadotropin regulation of Leydig cell function. Steroids 38(1): 35-44, 1981

The mechanisms involved in the regulation of the cell surface receptors for human chorio gonadotropin and mouse epidermal growth factor in cultured leydig tumor cells. Journal of Cell Biology 96(2): 521-526, 1983

Regulation of gonadotropin receptors and gonadotropin responses in a clonal strain of Leydig tumor cells by epidermal growth factor. Journal of Biological Chemistry 256(1): 179-183, 1981

Gonadotropin-induced receptor regulation and steroidogenic lesions in cultured Leydig cells. Induction of specific protein synthesis by chorionic gonadotropin and estradiol. Journal of Biological Chemistry 256(24): 12875-12882, 1981

Ultrastructural localization of immunoreactive human chorionic gonadotropin in cultured porcine leydig cells. Saez, J M Et Al (Ed ) Colloque Inserm (Institut National De La Sante Et De La Recherche Medicale), Vol 123 Developpements Recents De L'endocrinologie Du Testicule; (National Institute Of Health And Medical Research Colloquium), Vol 123 Recent Progress in Cellular Endocrinology Of The Testis; Meeting, Lyons, France, April 25-28, 1984 523p Editions Inserm: Paris, France Illus Paper 265-270, 1985